After years of selling the Mustang as a compact but powerful coupe and starting the pony car craze, Ford decides to downsize the Mustang and downplay the performance for the fuel crisis.
The resulting car was an unholy combination of Pinto and Maverick looks wise, without of a thread of it's previous heritage. Not only fugly aesthetically, it was fugly mechnically being based off a Pinto chassis and suspension (albiet with more sound deadening). Base engine was a 2.3L four with 88hp, and the "high output" engine was a 2.8L V6 with 105hp. The V8 disappeared. Inially there were 4 models - base coupe (notchback) and hatchback, the Ghia coupe and the Mach 1 hatchback.
Leading this fugly parade was the Ghia coupe (top 2 photos, 1975 model). Trying to look "European" (hence the Ghia name), it sported such Mustang appropriate features as a vinyl roof with matching side mouldings, hubcaps and a chrome luggage rack on top of the trunk. Look was more "Thunderbird" than "Mustang".
Surprisingly (being slower, uglier and more expensive than the '73 models) it was a huge success with sales tripling that of the '73 models. A V8 was added in '75 (making 140hp), and in '76 the Shelby inspired Colbra II was added to the lineup (bottom pic), but did little to help it's looks. Actually - the Colbra made it worse in 1978 when it sported gaudy Trans-Am inspired graphics.